Composite steel/concrete beams may buckle in hogging bending regions. As the top flange of I-beam in that arrangement is restricted from any translational deformation and twist, the web will distort during buckling presenting a phenomenon often described as restricted distortional buckling. There are limited studies available in the literature of restricted distortional buckling of composite st...

Failure in cold-formed steel beams is generally initiated by one of three instabilities: local, distortional, or lateral-torsional buckling. For cold-formed steel joists, purlins, or girts, when the compression flange is not restrained by attachment to sheathing or paneling, distortional buckling may be the predominant failure mode. Experimental results on cold-formed steel beams with unrestrai...

Open cross-section, thin-walled, cold-formed steel columns have at least three competing buckling modes: local, distortional, and Euler ~i.e., flexural or flexural-torsional! buckling. Closed-form prediction of the buckling stress in the local mode, including interaction of the connected elements, and the distortional mode, including consideration of the elastic and geometric stiffness at the w...

C and Z sections are two of the most common cold-formed steel shapes in use today. Accurate prediction of the bending performance of these sections is important for reliable and efficient cold-formed steel structures. Recent analytical work has highlighted discontinuities and inconsistencies in the American Iron and Steel Institute ~AISI! and Canadian Standards Association ~S136! design provisi...

Certain types of cold-formed sections, notably those composed of high-strength steel, some decking sections and racking sections may undergo a mode of buckling called distortional in which edge and intermediate stiffeners are inadequate to prevent lateral movement of the flanges which they support. The existing design methods in current standards and specifications are often not adequate to acc...

This paper presents an analytical method to calculate the buckling stress of a rectangular thin plate under nonuniform applied axial stresses. Two cases are considered, buckling of a plate simply supported on all four sides and buckling of a plate simply supported on three sides with one unloaded edge free and the opposite unloaded edge rotationally restrained. These two cases illustrate the in...

The objective of this paper is to provide work towards design methods to predict both the loss of stiffness and the available ductility for cold-formed steel members subject to cross-section deformations resulting from local and distortional buckling. Existing design specifications provide some guidance on how to predict the stiffness of cold-formed steel members, but no guidance on their avail...

Laminar structures have a high post-buckling strength reserve. Cold-formed steel profiles can be taken as a set of thin plate elements. Therefore it is necessary to design this type of profiles taking into account that reserve of strength in post-local buckling modes of failure. The method normally used to design this type of structures is based on the Effective Width concept. The Effective Wid...

A series of tests on cold-formed steel (CFS) wall plate system subjected to uplift force at the mid span of the wall plate is presented. The aim of the study was to study the behaviour and identify the modes of failure of CFS wall plate system. Two parameters were considered in these studies: 1) different dimension of U-bracket at the supports and 2) different sizes of lipped Cchannel. The lipp...